If you did that, then perhaps you could eventually have them go to interstellar civilian things as well? Imagine the fun if the Slaaz Empire suddenly has a colony in a system I claim, but their excuse is that it's just civilians and not an "official" venture. Of course they wouldn't let you just drive them off, though...
You could let the empire set "rules" on what the civilians are allowed to do, or mark systems or certain bodies as "nogo" areas. For grins, marking a valuable moon as "nogo" might only reduce the chance, and unless you ran a ship by to check on them you might not see one of your own civilian companies mining those resources you were saving for a rainy day.
Good idea!
(thinking out loud and rambling now)
The interesting question becomes whether civilian traffic is visible to the 'owning' player. Is that sensor contact an alien invader or an intrepid civilian mining expedition. Players might get used to the regular trade convoys but the sudden appearance of a civilian-financed colony expedition might send a few shivers through the equivalent of NORAD. It also raises the question of how 'civilian' colonies interact with state-sponsored colonies. An easy option would be for civilians to only migrate to existing colonies (using 'civilian' colony ships rather than the Empire's own colony ships) and then immediately become part of that population. Another option is independent colonies that are not under player control (although they might share a planet with an state-sponsored colony) and are treated almost like alien empires, except the player gets some tax income, perhaps trade income and maybe some sensor data if the colony has sensors. Players could 'nationalise' the colonies but there would have to be some penalty for doing so. A civilian colony expedition might decrease unrest as dissatisfied citizens leave their current planet and 'nationalising' a colony, or even attacking it, would raise unrest across the Empire.
Perhaps the chance of colonisation is determined by government type with democracies having a much greater chance of spawning civilian traffic and colonies than say a Stalinist Communist regme.
I guess this could also become the basis of 'pirates' if a new, out-of-the-way colony built a shipyard and a few raiders
. It would probably take a long time for that though under the regular rules so there have to be some coporate financing involved so the 'pirate base' could be established reasonably quickly.
Steve
